Bump xos libraries to version 4.0.0

Change-Id: Ibd20e72a594fa88df77904acc70e1f852ea2e15e
diff --git a/VERSION b/VERSION
index 40b6307..fb0ed55 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-1.4.0-dev
\ No newline at end of file
+2.0.0-dev
\ No newline at end of file